Sterolithography can take pretty much any shape from a file (Autocad or similar, not an image like a JPG) and make it solid. As coby stated, it ain't cheap and the result still needs a lot of clean up (the computer "draws" the form in increments so you don't get a smooth line, but rather a series of steps). The resin used is extremely hard and extremely brittle and is a major league pain in the butt to sand smooth.
Then there's the production costs. What'll kill you is the amount of rubber needed to make the molds, as that's the most expensive component. $65 US/gal for the stuff I used, just as a comparison. When I send my 1/1000 Enterprise conversions out for casting I generally spend $500-800 to have 25 made. Those are small kits, much smaller than your 1/48 Valk.
A shop with a rotocaster can make the parts hollow, using a special type of resin. Otherwise, it's a person tumbling the mold until everything sets (which means it can't be pressure cast). Alternatively, you make the parts in two halves - but that ups your rubber cost as you need more molds.